When your dad filed his return on paper, he should have claimed you as his dependent. Did he do that? His mailed return would be processed differently than an e-filed return and he should have received his full tax refund, with no need to wait for you to amend your incorrect return.
If he removed you as a dependent before he filed, then he will also have to amend in order to claim you.
Not sure what "child benefit" you mean--if you were 17 or older Dad does not get the child tax credit for you. He gets the $500 credit for other dependents which reduces his tax liability. And perhaps he gets education credits if you were a full-time student.
Maybe your Dad needs to post his own question here for further clarification for all concerned.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
